In late October 1950, the People's Republic of China (PRC) committed approximately 260,000 troops to combat in North Korea. The initial Chinese decision to intervene in the Korean conflict was based on a misperception of American commitment to halt communist expansion. American actions seemed to communicate the desire to avoid confrontation. The withdrawal of U.S. troops and the limited equipping and training of the South Korean army implied Washington's lack of interest in the fate of Korea. Therefore, Mao endorsed North Korea's proposal for the military reunification of Korea. China stood to gain international prestige and access to Soviet equipment and training at little cost. But the North Korean attack collapsed following the commitment of American and United Nations forces.

Chinese troops attacked and surprised the UN forces, inflicting heavy losses while driving them down the peninsula in disarray. Mao desired the quick expulsion of UN forces from Korea. To this end, the Chinese launched five brutal offensives between October 1950 and April 1951, but failed to realize their goal of imposing a communist government on an unified Korea.

Following the commencement of hostilities, the Chinese exaggerated their own military capabilities and underestimated the firepower and general effectiveness of American forces. But the Chinese army was unable to assimilate modern weaponry and tactics and, facing immense logistical difficulties, could not use its superior numbers to overwhelm United Nations forces. Inaccurate political and military assessments by Chinese leaders served to deny the PRC its goal of a unified Korea while ensuring it would be embroiled in a long and costly war.